The way I would look at it if I was thinking of buying it would be that the engine build if it has been done now has almost 50,000 Kms on it so its well used at that. if the engine is running fine get it checked by someone and if you are still interested then go for it and buy it.
I would have just had it looked over if everything looked and drove ok then I'd have bought it. If the mapping was an issue get it checked on the rollers. That would highlight any problems.